A stereoscopic display usually presents an observer with images with parallax from individual right and left eye viewpoints. There are several techniques of providing the two eyes of the observer with the parallax images to produce a stereoscopic viewing experience. In a first technique, the observer utilizes a pair of shutter or 3-dimensional (“3D”) glasses which transmit or block light from the viewer's eyes in synchronization with alternating the left/right image display. In a second technique, right eye and left eye images are alternatively displayed and directed towards the respective eyes of the observer but without the use of 3D glasses. This second technique is referred to as autostereoscopic, and is advantageous for 3D viewing because there is no need for the observer to wear any type of specialized glasses.
Autostereoscopic displays typically include a display panel, a specially designed backlight, and a specially designed light redirecting film disposed between the backlight and the display panel. The backlight provides a light guide having a light output area of nominally the same size as the display panel. Light sources disposed along opposite edges of the light guide are alternatively energized, causing the output area of the light guide to emit light alternatively at two different highly oblique angles. This light emitted by the light guide is intercepted by the light redirecting film (sometimes also referred to herein as 3D film), which converts the two different types of emitted light into alternating beams of light, one of which is directed to an observer's right eye and the other of which is directed to the observer's left eye. Placement of an electronically addressable display panel, such as an LCD panel, between the light redirecting film and the observer, and controlling the LCD panel to exhibit alternating right eye and left eye images in synchronization with the alternating light beams, allows the observer to perceive a 3-dimensional image.
The light redirecting film, which is typically cut to nominally the same size as the display panel and the output surface of the light guide, is held in place between the display panel and the light guide without actually being attached to either one. The resulting ability of the light redirecting film to move or shift in position subjects the film to potential warping and abrasion during the lifetime of the autostereoscopic display.